5 Side-Effects of Low-Carb Diets You Should Know About

To eat or not to eat carbs, that is the question. I often get asked if cutting calories and restricting the carb intake is a good strategy for losing weight fast, and I usually say that dropping pounds shouldn’t be a 2-week thing or a purpose in itself, but the consequence of a permanent diet and lifestyle change.

However, when it comes to the low-carb debate, I prefer pointing out the goods and the bads of this eating strategy, as the better you understand what LC actually involves, the more likely you are to make a decision that fits your diet habits and doesn’t threaten your health state in the long run. So I’ll briefly explain what LC diets are, then we’ll take a look at some of their potential side-effects.

What is a low-carb diet?

In very simple words, it’s a diet poor in carbohydrates and rich in proteins and fats. Poor in carbohydrates means that you remove most of your “cheat” foods, from bread, pasta and doughnuts to the less blamed potatoes, carrots or rice.

Although vegetables and fruits are allowed by most theoreticians of low-carb diets, lots of people embracing this eating style restrict the intake of veggies and fruits more than necessary and end up eating very few to no carbs at all.

Is this good or bad? Well let’s think at the role carbs have inside the human body: these nutrients are the main source of energy for our organism and they’re stored in the liver and muscles, for later use, when not broken down for immediate energy needs.

Besides fueling the muscles, carbs also provide energy for the normal functioning of the central nervous system, they’re involved in the fat metabolism and prevent proteins from being destroyed for energy. Carbs are surely important for the human body and this is why most low-carb diets actually allow one to take up to 20% of their daily calories from carbohydrates.

What are the benefits of LC diets?

Diets low in carbohydrates are often recommended to people dealing with chronic diseases and conditions like high blood pressure, diabetes, cardiovascular disease, metabolic syndrome, polycystic ovarian syndrome or chronic fatigue syndrome, thanks to their positive effects on the blood glucose and insulin levels.

Moreover, numerous studies have been published on the effects of LC diets on one’s weight, and a recent paper, reviewing 16,000 such studies, found low-carb diets to be very effective in removing excess pounds, when followed for a short period of time (less than 6 months in most cases). However, the long-term results are not so encouraging, as lots of the available studies show LC diets and moderate-carb diets have pretty similar results in terms of weight loss, in the long run.

And here is where the debate actually starts: if the low-carb diets are more effective than other eating strategies only when followed for short periods, they’re not exactly compatible with a permanent lifestyle change, right? Right! But they do support fast weight loss if only followed for a few weeks, correct? Yes, that’s correct! So should I or should I not go low-carb? To make the best decision, take a look at the risks below, and see if the benefits outweigh these potential side-effects.

5 potential side-effects you should consider

1. The yo-yo effect

LC diets favor fast weight loss, but studies have shown that most of this weight actually comes from muscle tissue and water, so you’re not actually getting rid of the fat underneath your skin, but of the glycogen stored in your muscles and of the extra water retained by your cells. Did you know that muscles burn twice the amount of calories that fat cells burn, regardless of your fitness level? So if you want to maintain a lean body in the long run, you need muscle tissue, not fat tissue.

Conclusion: Switching to a LC diet is not the best strategy for keeping weight under control in the long run, and the yo-yo effect is very likely to occur once you get back to your regular eating habits.

2. Vitamin and mineral deficiencies

A low-carb diet restricts the intake of vegetables and fruits, so if you adopt such a lifestyle, you’ll need to supplement the intake of minerals and vitamins, as your body needs these micronutrients in order to function properly. But this wouldn’t be a major problem if LC adepts would actually do it; however, people who go low-carb often forget to add vitamin and mineral supplements to their daily menu, and they end up with nutritional deficiencies that put their overall health at risk.

Conclusion: A low-carb diet often requires vitamin and mineral supplementation to avoid nutritional deficiencies. It’s up to you to decide if you prefer taking dietary supplements or getting your vitamins and minerals from veggies and fruits (which contain carbs, by the way).

3. Poor exercise performance

Cutting carbs means reducing the amount of fuel your muscles and brain receive. If you’re planning to follow the low-carb diet for a short period of time, your body won’t be able to adapt to this regimen well enough to support endurance performance. Although the organism can produce energy from the stored fats, for fueling the muscles during exercises, when it comes to strength training things are a bit more complicated.

The tougher the training routine is, the more glycogen your muscles burn, therefore the more carbs they need after the workout in order to recover properly. Bodybuilders and athletes often practice the ketogenic diet, which allows larger intakes of carbs before or after a workout, or periods of carb “re-feeds”, usually during weekends. But this is already a different approach, so if you plan to go low-carb just for the sake of quickly dropping some pounds, think of your muscles and brain before cutting the carbohydrates.

Conclusion: A low-carb diet won’t support proper exercise performance in the long run, unless mixed with periodic carb re-feeds. Muscle mass is very likely to decrease in a typical LC diet.

4. Ketosis and ketoacidosis

We won’t get into too many details as this topic is very complex, but in simple words, ketosis appears when the body burns fatty acids and ketones for energy, instead of using glycogen or glucose. The low-carb diet provides low amounts of glucose, so the liver quickly exhausts its glycogen stores. Once this happens, the liver needs to find another source of energy and uses the fatty-acids, which are turned into ketones.

The organism can function on ketosis, but when the amount of ketones that accumulates inside the body gets too high, ketoacidosis appears. This is a pathological metabolic state, which alters the pH of the blood and can be fatal. Still, assuming you won’t enter ketoacidosis, ketosis still has its drawbacks: it causes a strong diuretic effect, so unless you add lots of water, you can end up with severe dehydration.

Conclusion: Low-carb diets can lead to ketosis, which has strong dehydration effects. Moreover, ketosis can caused ketoacidosis, condition that can be fatal.

5. Digestive issues

LC diets decrease the metabolic rate, which means foods are digested slower, thus are more likely to accumulate inside the digestive tract. This increases the risk of constipation and coupled with the fact that LC diets are very poor in fibers, it leads to a very poor digestion.

Then, the absorption of nutrients becomes less efficient and the risk of developing irritable bowel, hemorrhoids, diverticulitis or even colon cancer increases. Fibers found in carbohydrates prevent the excessive accumulation of calcium, thus prevent the formation of kidney stones. Low-carbs means higher risk of kidney stones formation.

Besides these, the first days of LC diet are usually accompanied by the so-called brain fog, or mental lethargy caused by the sudden reduction in glucose (which is the main fuel for your brain) and by the loss of water from tissues. Then, the body fog or “induction flu” can appear, this meaning that the first days of LC can come with muscle cramps, nausea, headaches and a general weakness that makes you feel miserable and miss your much-blamed carbs. Oh, not to mention you’ll be a lot more irritable if you cut out most of the foods you used to enjoy!

So all in all, the low-carb diet may not be the best idea if you’re just doing it to lose weight fast. If you’re a bodybuilder, fitness junkie or athlete interested in the LC ketogenic diet, make sure you do it correctly. If you’re overweight, you can benefit from a short-term LC diet, BUT keep in mind that muscles burn more calories than fat tissues, so a healthy diet, with moderate consumption of carbohydrates, is better for weight management and overall health in the long run.